Process of making lampblack from acetylene.



No 779,728. PATENTED JAN. 10, 1905.- J. M. MOREHEAD.

PROCESS OF MAKING LAMPBLAGK FROM AGETYLENE. APPLICATION FILED JULY 2. 1904.

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UNITED STATES Patented. January 10, 1905 PATENT OFFICE.

JOHN M. MOREHEAD, OF CHICAGO, ILLINOIS, ASSIGNOR 'IO UNION CARBIDE COMPANY, OF NIAGARA FALLS, NEW YORK, A CORPORA- TION OF VIRGINIA.

PROCESS OF MAKING LAMPBLACK FROM ACETYLENE.

SPECIFICATION forming part of Letters Patent No. 779,728, dated January 10, 1905.

Application filed July 2, 1904. Serial No. 215,143. 7

To rtZZ whom, it 777/(LZ/ concern.-

Be it known that I, JoHN M. MOREHEAD, a citizen of the United States, residing at Ohicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Processes of Making Lampblack from Acetylene, of which the following is a specification.

It is well known that the incomplete combustion of acetylene results in the production of amorphous carbon. It is also known from the experiments of Berthelot and Vieille that compressed acetylene can be decomposed into its elements by an electric spark, an incandescent wire, or the explosion of a fulminate, the temperature of decomposition being placed by Lewes at 780 centigrade. United States Patent No. 671.672, granted April 9, 1901, to L. J. E. Hubou, describes a process of producing lampblack from acetylene by exploding the compressed gas out of contact with air. United States Patent No. 682,249, granted September 10, 1901, to Adolph Frank, describes the production of a carbon pigment by exploding a compressed mixture of acetylene and carbon monoxid or dioxid. In order to dissociate acetylene free from air, it is necessary to compress the gas to a higher point than is commercially practicable-say to three hundred and fifty or four hundred pounds per square inch and the explosion of the highly-compressed gas is so violent that it is liable to disrupt the strongest containers. For example, the explosion of 0.57 of a cubic foot of compressed acetylene in a tubular steel vessel having Walls three-fourths of an inch thick blew oli the end and split the side, producing a pressure, as calculated from the known tensile strength of the metal, of over two hundred and ninetythree thousand pounds per square inch.

1 have discovered that the dissociation-pressure of acetylene is decreased by the addition of air and that the required pressure varies inversely as the percentage of admixed air. The limiting amounts of air which produce a combustible or explosive mixture with acetylene at atmospheric pressure are about seventy-six per cent. and ninety-seven per cent, and the mixture of maximum explosibility contains eighty nine per cent. When the percentage of air is one, an initial pressure in excess of one hundred and fifty pounds per square inch is necessary to cause dissociation and the explosionpressure is dangerously high. When the air percentage is four and one-half, the explosion will occur at an initial pressure of sixty pounds, with an explosionpressure which for two and one-half cubic feet of gas averages five hundred and twelve pounds. From this figure the required initial pressure decreases with the increasing percentage of air to atmospheric pressure at seventy six per cent. As the percentage of admixed air is increased the explosion results in the production of an increased percentage of oxide of carbon and a decreased amount of free carbon. The explosion of a gas mixture containing seventy-six per cent. of air causes oxidation of a large amount of the carbon in the gas. The explosion of a mixture containing four and one-half per cent. of air gives a gaseous product containing hydrogen 93.00, carbon monoxid 3.84, and nitrogen 3.16. This analysis shows that the explosion reaction is not a mere oxidation or combustion of the elements of the acetylene, but a chemical dissociation of the gas. This reaction is believed to be peculiar to acetylene, and its course is unknown to me.

The present invention is a utilization of the above facts for the commercial production of lampblack.

In carrying out the process a mixture of acetylene and preferably four and one-half per cent. of air is compressed to sixty pounds per square inch in a water-jacketed steel cylinder with removable ends and is exploded by an electric spark, electrically-heated wire, or otherwise. The resulting hydrogen is allowed to escape, preferably into a receiver, one of the ends of the cylinder is removed, and the lampblack which fills the cylinder is blown out by compressed air, or it may be pushed out from the other end or raked out.

An apparatus which has been successfully employed is shown in the accompanying drawing, in which the figure is an axial section of the explosion vessel.

The vessel comprises a cylindrical body 1, preferably-of seamless steel, with flanged ends, surrounded by a water-jacket 2. The ends of the body are closed by covers 3 i, held in place by clamps 5, the ends of which engage the flanged ends of the body. The covers may also be water-jacketed. A clamp-serew 6, operated by a hand-wheel 7, passes through each clamp and bears against a central boss on the cover. A pipe 8 serves for the introduction of hydrogen to flush out the air in the vessel before introducing the gas mixture and for the escape of thehydrogen resulting from the explosion. This pipe leads to ahydrogenreceiver. (Not shown.) ApipeE) delivers the displaced air. A pipe 10 serves for the introduction of the gas mixture and a pipe 11 for the compressed air, preferably used to blow out the lampblack. A jump-spark electric igniter12 passes through the cover 4.

In operating the apparatus the air in the vessel is first expelled, as by the compressed hydrogen resulting from the previous explosion, and collected in a suitable receiver. The acetylene and four and one-half per cent. of air are thoroughly mixed, compressed to sixty pounds per square inch, and introduced through the pipe 10. The igniter 12 then explodes the mixture, and the resulting hydrogen is allowed to escape to its receiver. The cover 3 is then removed, and the lampblack is blown out by a blast of air under a pressure of onehalf pound per inch, the body of lampblack substantially filling the cylinder and flowing like a viscous or jelley-like solid. If preferred, the other cover, 4, may be removed and the carbon pushed out.

Acompressed mixture of acetylene and oxygen may be employed instead of one of acetylene and air, less oxygen than air being required to effect the explosion.

I claim 1. The process of making lampblack,Which consists in exploding a compressed gas mixture containing acetylene and oxygen, as set forth.

2. The process of making lampblack, which consists in exploding a compressed mixture of acetylene and air, as set forth.

3. The process of making lampblack,Which consists in exploding a compressed mixtureof acetylene and air, the proportion of air being in excess of one per cent, as set forth.

4:. The process of making lampblack, which consists in exploding a compressed mixture of acetylene and air, the proportion of air beingabout four and one-half per cent, as set forth.

5. The process of making lampblack,Which consists in exploding a gas mixture containing acetylene and oxygen at substantially the minimum pressure required to effect dissedation, as set forth.

6. The process of making lampblack,Which consists in exploding a mixture of acetylene and air at substantially the minimum pressure required to eli'ect dissociation, as set forth.

7 The process of making lampblack,Which consists in exploding a compressed mixture of acetylene and air, the proportion of air being about four and one-half per cent. and the pressure of the mixture being about sixty pounds per square inch, as set forth.

8. The process of making lampblai k, which consists in mixing definite amounts of aeetylene and air, compressing the mixture, removing the air. from an explosion vessel, filling the vessel with the compressed gas mixture, and exploding the mixture, as set forth.

9. The process of making lampblack,Which consists in exploding a gas mixture contain ing acetylene and oxygen and removing the resulting carbon from the xplosion vessel by an air-blast, as set forth.

In testimony whereof I afiix my signature in presence of two witnesses.

JOHN M, MOREHEAD.

IVitnesses:

Gr. WV. MEAD, H. G. ()RESPARK. 

